Ammonia（NH3） volatilization is a major pathway of nitrogen（N） loss from soil-crop systems.As vegetable cultivation is one of the most important agricultural land uses worldwide,a deeper understanding of NH3 volati...Ammonia（NH3） volatilization is a major pathway of nitrogen（N） loss from soil-crop systems.As vegetable cultivation is one of the most important agricultural land uses worldwide,a deeper understanding of NH3 volatilization is necessary in vegetable production systems.We therefore conducted a 3-year（2010-2012） field experiment to characterize NH3 volatilization and evaluate the effect of different N fertilizer treatments on this process during the growth period of Chinese cabbage.Ammonia volatilization rate,rainfall,soil water content,p H,and soil NH4~＋were measured during the growth period.The results showed that NH3 volatilization was significantly and positively correlated to topsoil p H and NH4＋concentration.Climate factors and fertilization method also significantly affected NH3 volatilization.Specifically,organic fertilizer（OF） increased NH3 volatilization by 11.77%-18.46%,compared to conventional fertilizer（CF,urea）,while organic-inorganic compound fertilizer（OIF） reduced NH3 volatilization by 8.82%-12.67% compared to CF.Furthermore,slow-release fertilizers had significantly positive effects on controlling NH3 volatilization,with a 60.73%-68.80% reduction for sulfur-coated urea（SCU）,a 71.85%-78.97% reduction for biological Carbon Power~？ urea（BCU）,and a 77.66%-83.12% reduction for bulk-blend controlled-release fertilizer（BBCRF）relative to CF.This study provides much needed baseline information,which will help in fertilizer choice and management practices to reduce NH3 volatilization and encourage the development of new strategies for vegetable planting.展开更多
A new way for preparing crosslinked starch matrix for slow release of carboxylic containing herbicides had been investigated and proposed. The matrix was crosslinked by formaldehyde in encapsulation process in order t...A new way for preparing crosslinked starch matrix for slow release of carboxylic containing herbicides had been investigated and proposed. The matrix was crosslinked by formaldehyde in encapsulation process in order to reduce the swellability and release rates, and to raise the performance of slow release and resistance to water. By using 2,4,5 T and 2,4 D as model herbicides, the improvement on swellability, encapsulation efficiency and release characteristic of the crosslinked matrix as compared with native starch had been evaluated. The effects of formaldehyde amount, herbicide contents, and particle sizes on the matrix behavior and release rates were also investigated.展开更多
基金supported by the National Key Science and Technology Project on Water Pollution Control and Treatment (Nos.2008ZX07101-006 and 2012ZX07506-006)
文摘Ammonia（NH3） volatilization is a major pathway of nitrogen（N） loss from soil-crop systems.As vegetable cultivation is one of the most important agricultural land uses worldwide,a deeper understanding of NH3 volatilization is necessary in vegetable production systems.We therefore conducted a 3-year（2010-2012） field experiment to characterize NH3 volatilization and evaluate the effect of different N fertilizer treatments on this process during the growth period of Chinese cabbage.Ammonia volatilization rate,rainfall,soil water content,p H,and soil NH4~＋were measured during the growth period.The results showed that NH3 volatilization was significantly and positively correlated to topsoil p H and NH4＋concentration.Climate factors and fertilization method also significantly affected NH3 volatilization.Specifically,organic fertilizer（OF） increased NH3 volatilization by 11.77%-18.46%,compared to conventional fertilizer（CF,urea）,while organic-inorganic compound fertilizer（OIF） reduced NH3 volatilization by 8.82%-12.67% compared to CF.Furthermore,slow-release fertilizers had significantly positive effects on controlling NH3 volatilization,with a 60.73%-68.80% reduction for sulfur-coated urea（SCU）,a 71.85%-78.97% reduction for biological Carbon Power~？ urea（BCU）,and a 77.66%-83.12% reduction for bulk-blend controlled-release fertilizer（BBCRF）relative to CF.This study provides much needed baseline information,which will help in fertilizer choice and management practices to reduce NH3 volatilization and encourage the development of new strategies for vegetable planting.
文摘A new way for preparing crosslinked starch matrix for slow release of carboxylic containing herbicides had been investigated and proposed. The matrix was crosslinked by formaldehyde in encapsulation process in order to reduce the swellability and release rates, and to raise the performance of slow release and resistance to water. By using 2,4,5 T and 2,4 D as model herbicides, the improvement on swellability, encapsulation efficiency and release characteristic of the crosslinked matrix as compared with native starch had been evaluated. The effects of formaldehyde amount, herbicide contents, and particle sizes on the matrix behavior and release rates were also investigated.
